canvas 相关文档
效果图展示
- 第一张是 随机颜色随机大小聚合 在一起效果
随机颜色
- 第二张是 随机背景图片随机大小分散 效果（这里我使用的图片都一样所以没展现出不同图片）
随机图片
案例完整代码
- 本实例是用
vue 来实现的，其他方法和 vue 类似，改为对应的语法即可实现效果。
- 案例用到了
vue 父子组件传值
父组件代码
<template>
<div id="home">
<div class="tags" ref="tags">
<circle-box :parentClientWidth="parentClientWidth" :parentClientHeight="parentClientHeight" :dataList="dataList"></circle-box>
</div>
</div>
</template>
<script>
import CircleBox from '@/components/content/circle/Circle.vue'
export default {
components: { CircleBox },
data() {
return {
parentClientWidth: 0,
parentClientHeight: 0,
// canvas 模拟数据
dataList: [
{
follow: 1,
image: 'http://39.99.139.115/demo/RB5.png'
},
{
follow: 2,
image: 'http://39.99.139.115/demo/RB5.png'
},
{
follow: 3,
image: 'http://39.99.139.115/demo/RB5.png'
},
{
follow: 4,
image: 'http://39.99.139.115/demo/RB5.png'
},
{
follow: 5,
image: 'http://39.99.139.115/demo/RB5.png'
},
{
follow: 6,
image: 'http://39.99.139.115/demo/RB5.png'
},
{
follow: 7,
image: 'http://39.99.139.115/demo/RB5.png'
},
{
follow: 8,
image: 'http://39.99.139.115/demo/RB5.png'
},
{
follow: 9,
image: 'http://39.99.139.115/demo/RB5.png'
},
{
follow: 10,
image: 'http://39.99.139.115/demo/RB5.png'
}
],
};
},
created() {},
mounted() {
this.getWidth();
},
methods: {
// 获取父盒子的宽度和高度
getWidth() {
this.parentClientWidth = this.$refs.tags.clientWidth;
this.parentClientHeight = this.$refs.tags.clientHeight;
console.log(this.$refs.tags.clientWidth);
}
},
};
</script>
子组件代码
<template>
<div>
<canvas id="myCanvas" :width="parentClientWidth + 'px'" :height="parentClientHeight + 'px'"></canvas>
</div>
</template>
<script>
export default {
// 接收数据
props: ['parentClientWidth', 'parentClientHeight', 'dataList'],
data() {
return {
dataListCopy: this.dataList
}
},
created() {
this.$nextTick(() => {
// 初始化
this.circleInfo()
})
},
mounted() {},
methods: {
circleInfo() {
let that = this
class Circle {
constructor(x, y, r, color) {
this.x = x
this.y = y
this.r = r
this.c = color ? color : this.getRandomColor()
}
// 随机颜色
getRandomColor() {
let r = Math.floor(Math.random() * 100) + 155
let g = Math.floor(Math.random() * 100) + 155
let b = Math.floor(Math.random() * 100) + 155
return `rgb(${r},${g},${b})`
}
}
class RandomCircle {
constructor(obj) {
this.c = document.getElementById(obj.id)
console.log(this.c)
this.ctx = this.c.getContext('2d')
this.dWidth = this.c.width
this.dHeight = this.c.height
this.fix = obj.fix || true
this.minMargin = obj.minMargin || 20
this.minRadius = obj.minRadius || 30
this.radiuArr = obj.radiuArr || [30, 30, 30, 30, 30, 30, 30, 30, 30, 30]
this.total = obj.total || 10
this.circleArray = []
this.circleNumber = 1
}
drawOneCircle(c, index) {
// console.log(c, index)
let ctx = this.ctx
ctx.beginPath()
ctx.strokeStyle = c.c
ctx.fillStyle = c.c
// 画圆
ctx.arc(c.x, c.y, c.r, 0, 2 * Math.PI)
ctx.stroke()
ctx.fill()
// ctx.textAlign = 'center'
// ctx.textBaseline = 'middle'
// ctx.fillStyle = 'black'
// ctx.font = '1rem 微软雅黑'
// ctx.fillText(that.dataListCopy[index].follow, c.x, c.y - 10) //圆内文字
let img = new Image()
img.src = that.dataListCopy[index].image
ctx.drawImage(img, c.x - c.r, c.y - c.r, c.r * 2, c.r * 2)
this.circleNumber++
}
check(x, y, r) {
return !(x + r > this.dWidth || x - r < 0 || y + r > this.dHeight || y - r < 0)
}
// 获取一个新圆的半径，主要判断半径与最近的一个圆的距离
getR(x, y) {
if (this.circleArray.length === 0) return Math.floor(Math.random() * 20 + 20)
let lenArr = this.circleArray.map((c) => {
let xSpan = c.x - x
let ySpan = c.y - y
return Math.floor(Math.sqrt(Math.pow(xSpan, 2) + Math.pow(ySpan, 2))) - c.r
})
let minCircleLen = Math.min(...lenArr)
let minC = this.circleArray[lenArr.indexOf(minCircleLen)]
let tempR = this.fix ? this.radiuArr[this.circleArray.length] : minCircleLen - this.minMargin
let bool = this.fix ? tempR <= minCircleLen - minC.r : tempR >= this.minRadius
return bool ? tempR : false
}
// 生成一个圆，随机生成圆心。
// 如果连续生成200次半径都没有合适的话，终止进程
createOneCircle() {
let x, y, r
let createCircleTimes = 0
while (true) {
createCircleTimes++
x = Math.floor(Math.random() * this.dWidth)
y = Math.floor(Math.random() * this.dHeight)
let TR = this.getR(x, y)
if (!TR) {
continue
} else {
r = TR
}
if (this.check(x, y, r) || createCircleTimes > 200) {
break
}
}
this.check(x, y, r) && this.circleArray.push(new Circle(x, y, r))
}
// 如果生成100次新圆都失败的话，终止方案。
// 如果生成100种方案都没有合适可用的话，终止进程。
init() {
let n = 0
while (this.circleArray.length < this.total) {
this.circleArray = []
let i = 0
while (this.circleArray.length < this.total) {
this.createOneCircle()
i++
if (i >= 100) {
break
}
}
n++
if (n > 100) {
break
}
}
// 根据半径从大到小画圆。
this.circleArray
.sort((a, b) => b.r - a.r)
.forEach((c, index) => {
this.drawOneCircle(c, index)
})
}
}
// console.log(this.circle);
const p = new RandomCircle({
id: 'myCanvas',
total: that.dataListCopy.length // 配置数量
})
p.init()
console.log(p)
console.log(p.circleArray)
}
}
}
</script>
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